T-CELLS FROM THE SMALL-INTESTINAL MUCOSA OF A DR4,DQ7 DR4,DQ8 CELIAC-DISEASE PATIENT PREFERENTIALLY RECOGNIZE GLIADIN WHEN PRESENTED BY DQ8

CD is an immunologic disease of the small intestine which is precipitated by ingestion of wheat gliadin. Most patients carry the HLA-DQ (alpha 1(*)0501,beta 1(*)0201) (DQ2) heterodimer. We recently reported that a preponderance of gliadin-specific T cells from the small intestinal mucosa of DQ2-positive CD patients were restricted by this DQ heterodimer. However, a small percentage of CD patients do not carry this DQ heterodimer, and most of them instead carry DQ (alpha 1(*)0301,beta 1(*)0302) (DQ8). Here we report that a majority of gliadin-specific T cells from the small intestinal mucosa of a DR4,DQ7/DR4,DQ8 heterozygous CD patient are restricted by DQ8. Thus, preferential presentation of gliadin-derived peptides to T cells by the CD-associated DQ2 and DQ8 molecules may be an initial and important immunopathogenic step in CD.